docs: document workbooks endpoint (#1762)

* docs: add missing Workbooks methods to api-ref.md

Adds documentation for methods not previously documented:
- populate_powerpoint (API 3.8)
- create_extract / delete_extract
- populate_permissions / update_permissions / delete_permission
- populate_revisions / download_revision / delete_revision
- schedule_extract_refresh

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* docs: add workbooks.add_tags, delete_tags, update_tags, update_connections, filter to api-ref.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

* docs: fix update permissions and links

* docs: add remaining API URLs

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Co-authored-by: Jordan Woods <13803242+jorwoods@users.noreply.github.com>
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
Co-authored-by: Brian Cantoni <bcantoni@salesforce.com>

Author: 3 people